Self-Defence as a Circumstance Precluding Wrongfulness: Understanding Article 21 of the Articles on State Responsibility

Abstract

This study considers self-defence in its function as a circumstance precluding wrongfulness, as codified in Article 21 of the ILC's Articles on State Responsibility. The study examines the development of this provision in the work of the ILC and considers relevant practice by States and international tribunals in relation to the defence. The study explains that self-defence has two functions in international law. The right of selfdefence, codified in Article 51 of the UN Charter and recognised in customary international law, is an exception to the prohibition of force. In the ILC terminology, the right of self-defence is a primary rule. The circumstance precluding wrongfulness of selfdefence, contained in Article 21 ARS, serves to preclude the wrongfulness of potential breaches of obligations (other than the prohibition of force) binding the States involved in an armed conflict, so long as the breach of those obligations is a collateral effect of self-defensive forcible measures adopted in conformity with the requirements of the right of self-defence under international law. In the ILC terminology, this is self-defence in its function as a secondary rule.

Neutral Arms Transfers and the Russian Invasion of Ukraine

“…45 Self-defence within the meaning of Article 21 serves to cover any breaches of the rights of the aggressor State that may be incidental to the exercise of the victim State's self-defence pursuant to Article 51 of the UN Charter. 46 The question thus becomes whether neutral States supplying arms to Ukraine are using force in collective self-defence of Ukraine. If they are, wrongfulness may be precluded.…”

“…W Heinstchel von Heinegg, '"Benevolent" Third States in International Armed Conflicts: The Myth of the Irrelevance of the Law of Armed Conflict' in M Schmitt and J Pejic (eds), International Law and Armed Conflict: Exploring the Faultlines. Essays in Honour of Yoram Dinstein (Martinus Nijhoff 2007) 554; M Bothe, 'The Law of Neutrality' in D Fleck (ed), The Handbook of International Humanitarian Law (3rd edn, OUP 2013) 550. International and Comparative Law Quarterly to the exercise of the victim State's self-defence pursuant to Article 51 of the UN Charter 46. The question thus becomes whether neutral States supplying arms to Ukraine are using force in collective self-defence of Ukraine.…”

Circumstances Precluding Wrongfulness in International Investment Law

“…in relation to commercial matters, which suggest that self-defence precludes wrongfulness for other breaches that are collateral to the use of force in self-defence. 62 As often is the case when the existence of a customary rule is debated, a more sceptical reader might distinguish these instances as relating to the operation of, or exceptions within other primary rules. The sceptic would find support in Oil Platforms, where the issue of self-defence in terms of the 2001 ILC Articles was put squarely before the ICJ.…”

May the Force Be with You: The Legal Classification of Intervention by Invitation

“…A recent example of such a further discussion centres on one of these circumstances: self-defence. SeePaddeu (2015);Paddeu (2017);, but also Christakis andBannelier (2007);Christakis and Bannelier (2009);and Van Steenberghe (2012).108 Crawford's Second report, supra n.106, p. 60, para. 230; Crawford (1999), p. 444;), p. 303.…”